Demetri Portelli tells THR, “3D is not just hitting a button in post. It is something discussed and planned and it is very creative."

In making Jean-Pierre Jeunet’s lastest film, The Young and Prodigious T.S. Spivet, stereographer Demetri Portelli was out to prove that 3D is creative, and that quality 3D footage could be shot on schedule and on budget.

"3D is not just hitting a button in post," he told The Hollywood Reporter. "It is something discussed and planned and played with and it is very creative."

Portelli, whose credits as a stereographer include Martin Scorsese's Hugo, claimed the use of 3D was unjustly blamed in some circles for that film's exceeding budget and schedule. "It was just a large project," he explained. "Spivet on the other hand had a $30 million budget and couldn't afford a single extra day. We had a very ambitious dramatic story with lots of location work in Alberta [Canada] and it was my job to bring in the 3D equipment and a small 3D crew for less than 10 percent of the total budget."

He claimed: "In the end, we were considerably under that cost [and] we didn't have to fix or throw out any shots."

T.S. Spivet tells the story of a 12-year-old cartographer on a solo journey from his Montana home to pick up an award at the Smithsonian Institution. In a review of the film from the San Sebastian Film Festival, THR’s Jonathan Holland wrote: "The film's greatest achievement is in the way the accomplished 3D treatment ... emerges entirely naturally, as the precise expression of a gifted child’s vivid imagination."

According to Portelli, Jeunet made explicit reference to Hugo in crafting the 3D. Specifically, he wanted to replicate the signature shot in Hugo where Sacha Baron Cohen's character looms menacingly out of the screen, while questioning Hugo in the train station.

"He wanted the 'Sacha shot' for a scene in a classroom where the boy is being reprimanded by the teacher for not having done his homework well enough," said Portelli.

Another takeaway from Hugo was the addition of goose feathers to simulate prairie dust motes, placed in front of a light source to add volume to the dusty attic or the kitchen on the ranch. "We didn't treat the screen as a picture window where everything falls deep in space," he explained. "I took my cue from the success of Hugo and explored as much negative space (the space in from of the screen) as positive space for this film, achieving a really nice balance for intimacy with the audience."

The entire film was shot natively in 3D and, according to Portelli, was the first to use lightweight Arri Alexa M cameras on a variety of Cameron Pace Group rigs, including a Steadicam rig. The digital intermediate depth grade was performed under Portelli's supervision at Digimage, Paris. "Native shooting is a lot cheaper than converting a film [from 2D into stereo]," Portelli said. "The problem is that stereographers and cinematographers can't seem to win when a large corporation – such as a conversion company -- gives a studio a package deal for five movies.

"I can see how, on a corporate level, conversion works for a large studio. After the film is shot, they can make a decision on whether they want a 3D version. But it's such a shame for directors and cinematographers who want to get hands on with stereo."

A fan of the director's previous work — films such as Amelie and A Very Long Engagement— Portelli made the first approach to Jeneut when Hugo was shooting in Paris in 2010.

"I asked the crew if anyone could get me his email, since I had loved his work since film school and I had a particular feeling he was born to shoot 3D. Although I did not meet him until he was planning to come to Canada [to shoot Spivet], he mailed me that he was writing a script and thinking about 3D as he was writing."

When Portelli joined the project in January 2012, Jenuet had already devised detailed storyboards with notes on the 3D and VFX. In the film, 3D motifs mark the chapters to the journey with a paper pop-up book and pencil sketches that 'float' off the page.

Portelli cited one example of Jeunet's notes for a classroom scene. "It reads: 'Suddenly, freeze frame. T.S. and Stenpock seem to separate from their respective bodies and their ghosts float into the 3D space. Time in the background stands still while the dialogue continues with the 3D ghost figures.'"

He said, "Jeunet uses the layers as an added tool into the psychology of the character and for a personal connection to the audience that other films have not exploited. He uses text and graphics to illustrate what the boy is thinking or how fast he is running to catch a train."

Portelli admitted he was initially concerned that Jeunet might overplay the 3D. "In Delicatessen, for example, he places so much in the foreground, I was worried that if he transferred that style into 3D, then the stereo may be too distracting, so I advised him to be careful. But his plan for Spivet was quite understated and simple."

Likening his work to scoring a soundtrack, Portelli said, "There is no mathematical formula telling you where the 3D should be in a shot. The process is organic and has to be worked out on set. Before almost every shot, Jean-Pierre and I would have a quick meeting to decide the depth and the plane -- where the negative and the positive space should be to maintain proper 3D.

“Both Martin and Jean-Pierre would change the 3D on additional takes to play with the range of the depth available. I merely operate and manage the depth, suggest and maintain the plan, but these particular directors are choosing the big 3D moments and the fun, engaging times to interact with the audience."